Class: BlackStack::Bots::Browser

Inherits:
Watir::Browser
  • Object
show all
Defined in:
lib/browser.rb

Constant Summary collapse

LOCKFILENAME = 
'/tmp/blackstack.bots.browser.lock'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Browser

Returns a new instance of Browser.



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# File 'lib/browser.rb', line 7

def initialize()
    self.lockfile = File.open(LOCKFILENAME, 'w+')

    n = 20 # timeout in seconds

    # wait the lock file /tmp/blackstack.bots.browser.lock
    self.lockfile.flock(File::LOCK_EX)
    begin
        # get list of PID of all opened chrome browsers, before launching this one 
        pids_before = `pgrep -f chrome`.split("\n")
        # setup driver
        client = Selenium::WebDriver::Remote::Http::Default.new
        begin
            client.read_timeout = n # for newest selenium webdriver version 
        rescue => e
            client.timeout = n # deprecated in newest selenium webdriver version
        end                    
        options = Selenium::WebDriver::Chrome::Options.new
        options.add_argument('--headless')
        # setup user agent with-out the keyword "headless"
        # otherwise, our scraper may be detected as a bot and blocked
        options.add_argument("user-agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64)")
        #+"AppleWebKit/537.36 (KHTML, like Gecko)"
        #+"Chrome/87.0.4280.141 Safari/537.36")

        # Add this parameter to run Chrome from a root user.
        # https://stackoverflow.com/questions/50642308/webdriverexception-unknown-error-devtoolsactiveport-file-doesnt-exist-while-t
        options.add_argument('--no-sandbox') 

        driver = Selenium::WebDriver.for :chrome, :options => options, http_client: client
        # create the browser
        super(driver)
        # get list of PID of all opened chrome browsers, after launching this one 
        pids_after = `pgrep -f chrome`.split("\n")
        # store list of PID regarding this launched browser
        self.pids = pids_after - pids_before
    rescue => e
        # unlock the file
        self.lockfile.flock(File::LOCK_UN)
        # raise the error
        raise e
    ensure
        # unlock the file
        self.lockfile.flock(File::LOCK_UN)
    end
end

Instance Attribute Details

#lockfile ⇒ Object

Returns the value of attribute lockfile.



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# File 'lib/browser.rb', line 5

def lockfile
  @lockfile
end

#pids ⇒ Object

Returns the value of attribute pids.



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# File 'lib/browser.rb', line 5

def pids
  @pids
end

Instance Method Details

#close ⇒ Object

initialize



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# File 'lib/browser.rb', line 54

def close
    # kill all pids regarding this browser
    self.pids.each { |pid| `kill -9 #{pid} >/dev/null 2>&1` }
end

#quit ⇒ Object

close



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# File 'lib/browser.rb', line 59

def quit
    # kill all pids regarding this browser
    self.pids.each { |pid| `kill -9 #{pid} >/dev/null 2>&1` }
end